Lath board



Dec. l1, 1928.

v G. A. BUTTRESS LATH BOARD Filed4 March 15, 1926 2 Sheets-Shee l ITI l/Pfar Dec. 11, 1928.

G. A. BUTTRESS LATH BOARD 2 Sheets-Sheet 2 Filed March l5, 1926 construction in a panel PATENT OFFICE.

(zrllilOBGE A. BUTTRESS, OF LOS ANGELES, CALIFORNIA.

LATE BOARD.

Application led March-15, 1926. Serial No. 94,731.

This invention particularly pertains to aI lath ot the type embodying a panel consisting of a layer of plaster interposed between fibrous facing sheets. j

An object of the-invention is to provide a of the above character whereby such bond will be afforded between the panel and a coating of plaster being applied thereto as to minimize rolling of the plaster under the trowel and in which the requisite bonding structure will be attained without exposing any portions of the plaster layer of the panel to the plaster coating thus overcoming the objectionable features inci dent to many composition lath panels heretofore devised in which the facing sheet is -formed with apertures to provide bonding means.

Theinvention resides generally in forming a paper facing sheet with a series of narrowribs of arched vcross section, which ribs are produced by pressing the sheet between embossing elements whereby the material ot the sheet is stretched to form the ribs thereby permitting the ribs being` subjected to the pressure required in forming the panel without pressing the portions of the sheet forming the ribs back to the normal or near normal position. The invention contemplates forming the embossed ribs to project from either or both sides of the facing sheet so that the lath board surfaced thereby may be provided with either a series of raised ribs or a series of grooves or a series of both ribs and grooves, as occasion may require to afford such irregularity in the surface contour of the board as to prevent rolling of plaster coating being applied thereto.

The invention is illustrated in the accompanying drawings, in which Fig. 1 is a `plan view ot-,a portion of the lath panel showing a preferred construction;

Fig. 2 is a view in section as seen on the line 2*-2 of Fig. 1;

Fig. 3 is a view in section as seenon the line 3-3 of Fig. 1;

Fi 4 is a vlew in elevation of a finished pane Fig. 5 is an enlarged detail in section depicting one of the embossed ribs formed in the facing sheet;

Fig. 6 is a view in section showing the man-VA Fig. 8 is a view in section as seen on the line 8 3 of Fig. 7;

Flg. 9 is a plan view of another modification of the invention;

Fig. 10 is a View in section as seen on the line 10--10 of Fig. 9;

. Fig. 11 is a plan View showing another modification Fig. 12 1s a vlew 1n section taken on the line 12-12 of Fig. 11;

Fig. 13 is a plan view of a further modification;

Fig. 14 is a sectional view as seen on the line 14-14 of Fig. 18.

Referring to the drawings more specifically A and B indicate respectively a facing s eet and a backing sheet between which 1s lnterposed a layer of plaster C. The sheets A and B are imperforate and are preferably formed of paper or pulp board, which is fibrous and ot suitable character to permit `plaster to adhere thereto. The plaster C is preter'ably composed of gypsum and sawdust muted with water to form a plastic mass which is interposed between the sheets A and B while in a wet unstable condition and thereafter allowed to set and harden', as is common 1n plaster wall board construction. It is obvlous that any suitable cementitious material may be employed to form the plaster layer C.

The essence of the present invention resides in forming the facing sheet A with ribs D ot' substantially arcuate or arched cross section as shown in Figs. 1, 4, 7 and 9, but which may,

in some instances be straight, as shown in Figs. 11 and 13, in which latter'case, they may be int-ersected either obliquely, as shown in Fig. 11 or at right angles,..as shown in Fig. 13. The ribs D are preferably formed to project from one side of the sheet, as shown in Figs. 1 and 7, or theymay be formed to project from opposite sides of the sheet as shown in Fig. 9. Either side of the sheet A may be presented to the plaster C and where the embossments are formed Vto project from one side of the sheet, they may be presented outwardly as shown in Fig. 1, or inwardly'as shown in Fig. 7 Y

The ribs D constitute embossments which project from the face of the sheet; there being iat areas adjacent the embossments constituting the major surface of the sheet. The arrangement of the embossments. as contemplated by my invention is such that the embossments will constitute interruptions between the adjacent Hat areas in all directions crossing the sheet, so that in applying mortar to the finished lath board by means of a trowel, the interruptions afforded by the embossments will engage the mortar on advancing the trowel in any direction, and thereby prevent rolling up of the mortar under the trowel. The intersection of the embossments inthe arrangement shown in Figs. l1 and 13 not only affords the interruptions as above mentioned, but also provides interruptions along the lengths of the embossments, which may also be stated with regard to the serpentine arrangement of the embossments shown in Figs. l, 4, 7 and 9 as in the latter arrangement the bends formed at intervals throughout the lengths of the serpentine embossments constitute intersections alording interruptions along the leno'ths of such serpentine embossments.

Iii manufacturing the lath board, I prefer to employ the method illustrated in Fig. 7, consisting in feeding the facing sheet A between a' pair of embossing rollers 2l and 22, having appropriately arranged cooperating ribs and grooves on their peripheries operable on drawing the facing sheet between the rollers to form the desired ribs on the facing sheets. The rib D is then passed over a direction roller 23 and fed between a pair of spaced forming rollers 24 and 25 and delivered onto a horizontally extending endless belt 26. The backing sheet B is fed around the upper forming roller 24 and passed between the rollers 24 and 25 in the direction of and parallel to the facing sheet A. The plastic material, in a wet unstable condition, is fed between the sheets A and B as they pass between the forming rollers 24 and 25; the rollers 24 and 25 operating to compress the plaster between the facing sheets and thereby forming a panel. The plaster being soft flows into the recessed portions of the facing sheet presented thereto immediately before passing between the forming rollers 24 and 25, thus filling the recesses with a body of plastic before the body and facing sheet are subjected to the pressure of the forming rollers 24 and 25 whereby the raised portions projecting from the underside of the facing sheet A' passing over the roller 25 will be but slightly depressed, as indicated in full lines 1n Fig. 6 in relation to dotted lines. This depression of the projections or ribs is further resisted by reason4 of the arch formation of the rib.

In this manner the sheets A and B are fed continuously from suitable reels so as to form a ribbon which is carried forward on the endless belt 26 by reason of its frictional engagement with the latter; the ribbon being subsequently cut into panels of suitable lengths and widths, being preferably formed about four feet in length and sixteen inches in width. fected after the plaster has set. The panels are then allowed to dry, being preferably kiln-dried.

I claim l. A lath board comprising a facing sheet, a backing sheet, and a layer of plaster interposed between said sheets; said facing sheet being formed with a series of ribs of arcuate cross section projecting from flat areas, said ribs being arranged to afford interruptions This cutting of the panels is ef betweenv the flat areas of the sheet in all d'iv rections crossing the sheet.

2. A lath board comprising a facing sheet, a backing sheet, and a layer of plaster interposed between said sheets; said facing sheet being formed with a series of embossments arranged to afford interruptions throughout the surface of the sheet in all directions crossing the sheet and also being formed to afford intersecting embossments to provide interruptions along the lengths'of the embossments.

3. A lath board comprising a facing sheet,-

a backing sheet, and a layer of plaster interposed between said sheets; said facing sheet being formed with a series of embossments arranged to afford interruptions throughout the surface of the sheet i in all directions crossing the sheet; said embossments being formed to provide. interruptions along the lengths thereof.

In testimony whereof, I have aflixed my signature.

GEORGE A. BUTTRESS. 

